Slots on this function:
A relation-universe of a relation of any arity is a class
from which is drawn every item in every tuple of the relation.
Like EXACT-DOMAIN, it is exactly those items and no other.
Thus, to state that the universe of a relation is covered by
some class, one can state that the relation-universe is a subclass
of the covering class.
- Arity: 2
- Domain: Relation
- Range: Class
(<=> (Relation-Universe ?Relation ?Type-Class)
(And (Relation ?Relation)
(<=> (Exists (?Tuple)
(And (Member ?Tuple ?Relation)
(Item ?X ?Tuple)))
(Instance-Of ?X ?Type-Class)))))